1. Field of the Invention
The present invention relates to improvements in folding foot step assemblies of the type that are used on vehicles such as trucks and railroad cars to provide a convenient means to ascend and descend the vehicle. More particularly, the present invention relates to providing folding step assemblies with an improved anti-skid, friction grip, stand-on surface having a generally clover-leaflet-shaped perimeter, with the stand-on surface being interrupted by three elongate openings that are spaced from the perimeter and arrayed about an uninterrupted central region of the surface, with an upwardly-opening recess being defined by a narrow upstanding rim that runs along the perimeter of the stand-on surface and by narrow upstanding rims that encircle the openings, with anti-skid material nested in the recess, covering the floor of the recess, and cooperating with the narrow upstanding rims to provide a stand-on surface that features a friction-grip texture in the central region and in regions of the stand-on surface located between the openings and between the openings and the perimeter.
2. Prior Art
Large vehicles such as railroad and rail transit cars, trucks, fire trucks, trailers, motor homes, campers and the like require some means to facilitate climbing up and down the vehicle. Various devices have been proposed to facilitate ascending and descending such vehicles.
A folding foot step assembly for vehicles that has been in wide use for many years is described and illustrated in U.S. Pat. No. 4,462,486 issued Jul. 31, 1984 entitled FOLDING FOOT STEP, referred to hereinafter as the xe2x80x9cFolding Step Patent,xe2x80x9d the disclosure of which is incorporated herein by reference. Reference also is made to U.S. Pat. No. D-276,716 issued Dec. 11, 1984 entitled FOLDING STEP, which discloses an attractive appearance for a folding step.
The Folding Step Patent discloses a bracket member for mounting on the side of a vehicle, and a step member having a relatively wide front region that defines a stand-on surface located forwardly with respect to a relatively narrow rear region that is pivotally connected to the bracket member to enable the step member to pivot relative to the bracket member between an xe2x80x9cextendedxe2x80x9d or xe2x80x9cusexe2x80x9d position and a xe2x80x9cfoldedxe2x80x9d or xe2x80x9cstoragexe2x80x9d position. When the step member is in its extended or use position, the stand-on surface extends substantially horizontally and faces upwardly for being engaged by shoes and boots of those who use the folding step assembly to ascend or descend the side of the vehicle on which the folding step is mounted. When the step member is in its folded or storage position, the stand-on surface extends substantially vertically and faces toward the side of the vehiclexe2x80x94an orientation that minimizes the extent to which the folding step assembly projects away from the side of the vehicle.
The configuration of the stand-on surface, as defined by the perimeter of the step member disclosed in the Folding Step Patent, is much like that of a leaflet of a xe2x80x9cthree-leafletxe2x80x9d white clover plant commonly found in the lawns of mid-western America. More specifically, the perimeter of the stand-on surface is defined by opposite sides that diverge as they extend forwardly from the relatively narrow rear region of the step member (so as to increase the width of the stand-on surface as the stand-on surface extends forwardly from the relatively narrow rear region of the step member), and by a rounded, generally xe2x80x9cC-shapedxe2x80x9d front that connects smoothly with the opposite sides (at opposite xe2x80x9cendsxe2x80x9d of the xe2x80x9cCxe2x80x9d of the front) to complete the perimeter of the stand-on surface. Stand-on surfaces that have a perimeter of this character are referred to herein as being xe2x80x9cclover-leaflet-shapedxe2x80x9d and as having a xe2x80x9cclover-leaflet shape.xe2x80x9d
The Folding Step Patent discloses a folding step assembly having a stand-on surface of clover-leaflet shape that is provided with a single relatively large, centrally located, kidney-shaped opening that is spaced from and substantially aligns with the curved C-shaped front of the step member. The kidney-shaped opening permits mud and other shoe- or boot-carried debris to escape when a shoe or boot is moved onto and pressed against the stand-on surface. Those who pivot the step member between its extended and folded positions also find the kidney-shaped opening to be useful in that it provides a passage through which the fingers of one hand can be inserted when it is necessary to grasp the step member to effect its pivotal movement.
While the referenced Folding Step Patent discloses the use of protruding diamond shaped elements on a clover-leaflet-shaped stand-on surface for the purpose of providing anti-skid characteristics, it is desirable to provide a significantly improved slip resistant, anti-skid, stand-on surface that is much less likely to permit the soles of shoes and boots to slip and slide thereon.
Other improvements that aid in providing an anti-skid surface also are desirable if they can be implemented without discarding the well accepted and well liked features of the folding step assembly disclosed in the Folding Step Patent, including the clover-leaflet shape of the stand-on surface and the advantages offered by the presence of a kidney-shaped opening that parallels the C-shaped front of the stand-on surface at a location spaced therefrom.
During recent years, significant effort has been devoted to the development of anti-skid materials that can be applied to exterior surfaces such as roadways, walkways and steps, and to interior surfaces such as the floors of bath tubs and shower stalls, as well as interior walkways and steps, to diminish unintended slippage thereon. This effort has resulted in the development of anti-skid formulations that can be applied as a spray or in liquid or paste form to surfaces where the newly applied material cures otherwise hardens over time, and in the development of adhesive-backed sheets of anti-skid material having a peel-off backing that enables the adhesive-backed sheets to be applied quickly and easily to surfaces to immediately provide desired anti-skid characteristics. Inasmuch as new types of anti-skid material and improvements in existing types of anti-skid material are steadily being developed, it is desirable to find an appropriate manner in which now-existing and newly developed forms of anti-skid material can be utilized on clover-leaflet-shaped folding step assemblies to enhance the anti-skid characteristics thereof without diminishing or distracting from other well accepted and advantageous features thereof, and while also providing other useful improvements therein.
The present invention addresses the foregoing and other drawbacks of the prior art by providing a folding step having a clover-leaflet-shaped stand-on surface that defines a wide-area recess wherein anti-skid material is nested. The recess is defined, at least in part, by a narrow rim that extends along the perimeter of the clover-leaflet-shaped stand-on surface to protect edge regions of the anti-skid from edge abrasion and/or from being peeled off of the step member.
The provision of a folding step assembly of the type having a clover-leaflet-shaped stand-on surface with anti-skid material nested in a wide-area recess bordered by a narrow, upstanding, perimetrically extending rim represents one novel feature of the present invention. The provision of a wide-area recess (i.e., a recess that extends across the vast majority of the top surface of a metal step member except where rim formations are provided near edge regions thereof) constitutes an arrangement that can be used with a wide variety of present-day anti-skid materials, and is well suited for use with new anti-skid materials as they are developed.
In preferred practice, the clover-leaflet-shaped stand-on surface is interrupted not only by an elongate kidney-shaped opening that is spaced from and substantially parallels the curved C-shape front of the stand-on surface, but also by a pair of other elongate openings, each of which parallels one of the opposed sides of the stand-on surface that extend between the curved C-shaped front and the relatively narrow rear region of the step member. In preferred practice, these three elongate openings are spaced short distances from the perimeter of the stand-on surface, and are arrayed about an uninterrupted central region of the stand-on surface, with the recess that carries the anti-skid material extending across the central region, between the openings, and between the openings and the perimeter of the stand-on surface. These three openings preferably are of about the same size and all are designed and positioned to provide finger-receiving passages that can be used when one needs to grip the step member from the front or from either of the sides of thereof to pivot the step member between its extended and folded positions.
The provision of a clover-leaflet-shaped step member with three elongate openings wherein one is generally kidney-shaped (spaced from and paralleling the C-shaped front) and the other two are elongate and have rounded ends (each spaced from and paralleling a separate one of the opposed sides of the step member) to provide hand holds that can receive the figures of one""s hand when a need exists to grasp the step to pivot it between its folded and extended positions, has proved to be quite a useful feature unto itselfxe2x80x94a feature that is not limited to use with clover-leaflet-shaped step members that carry anti-skid material nested in an upwardly opening recess.
In preferred practice, the area of the stand-on surface and the combined area of the three elongate openings has a ratio of about two-to-one. While the stand-on surface is not limited to a particular size, in preferred practice the stand-on surface offers about 24 to about 25 square inches of upwardly facing support area to boots and shoes that engage it; and, the combined area of the three openings that interrupt the stand-on surface is within the range of about 12.0 to about 12.5 square inches so as to provide enough open space to enable mud and other shoe and boot-carried debris to discharge therethrough as shoes and boots are moved onto and pressed into engagement with the stand-on surface. The resulting ratio of approximately two-to-one can, of course, be preserved if the size of the stand-on surface is scaled up or down to provide step member sizes that are better suited to a particular application.
In preferred practice, the borders of the large-area recess that nests the anti-skid material are defined by relatively thin, upstanding rims that are at least as tall (they extend at least as far above the floor of the recess wherein the anti-skid material is nested) as is the average thickness of the anti-skid material. Because the anti-skid material is provided with a rough top surface that typically is defined by abrasive particles or the like held in place by a suitable binder (much like a sheet of coarse sandpaper), the thickness of the anti-skid material varies between the peaks and valleys between the abrasive particles. To protect edge regions of the anti-skid material from undue edge abrasion and/or from being peeled away from the floor of the recess, the upstanding rims preferably are at least as tall as the average thickness of the body of anti-skid material carried in the recess.
In preferred practice, the upstanding rims include a narrow, uninterrupted, upstanding rim that defines the perimeter of the stand-on surface (i.e., it extends along at least a majority of the lengths of the two opposite sides and the C-shaped front of the stand-on surface without interruption), and also includes narrow, uninterrupted, upstanding rims that ring (i.e., that extend in an uninterrupted fashion about at least a majority of the perimeters of) each of the three elongate openings (i.e, the kidney-shaped opening that is spaced from and substantially parallels the curved front, and the elongate openings that are spaced from and substantially parallel the f opposite sides of the stand-on surface). The linear length of these four rims preferably totals about 48 to about 52 inches which gives a narrow ridge of solid metal adjacent the perimeter of the stand-on surface and adjacent the perimeters of the three openings for directly engaging the soles of shoes and boots that are moved onto and pressed into engagement with the stand-on surface. This combination of lengthy reaches of narrow upstanding rim formations (that extend in a variety of directions as they wrap about the perimeters of the stand-on surface and the openings that interrupt the stand-on surface) and the wide-area friction grip surface provided by the recess-carried anti-skid material, taken together with the presence of an uninterrupted central region (of the anti-skid material that almost always engages shoes and boots supported by the stand-on surface) surrounded by three sizable elongate openings that permit shoe- and boot-carried debris to pass therethrough has been found during tests to provide a combination of features that cooperates to significantly enhance the slip-resistance of the step member in comparison with the folding step design that is disclosed in the referenced Folding Step Patent.